ucos.c

ppc860平台上移植uc OS的实例

*                 returns OS_TASK_DEL_REQ if a  task requested to delete SELF
*                 returns OS_NO_ERR       if no task requested to delete SELF
*             if 'prio' is other than OS_PRIO_SELF:
*                 request that the task be deleted
*********************************************************************************************************
*/
/*$PAGE*/
UBYTE OSTaskDelReq(UBYTE prio)
{
    BOOLEAN  stat;
    OS_TCB  *ptcb;


    if (prio == OS_LO_PRIO) {                                   /* Not allowed to delete idle task     */
        return (OS_TASK_DEL_IDLE);
    }
    if (prio >= OS_MAX_TASKS && prio != OS_PRIO_SELF) {         /* Make sure task priority is valid    */
        return (OS_PRIO_INVALID);
    }
    if (prio == OS_PRIO_SELF) {                                 /* See if task to delete is requesting */
        OS_ENTER_CRITICAL();
        stat = OSTCBCur->OSTCBDelReq;                           /* Return request status to caller     */
        OS_EXIT_CRITICAL();
        return (stat);
    } else {
        OS_ENTER_CRITICAL();
        if ((ptcb = OSTCBPrioTbl[prio]) != (OS_TCB *)0) {       /* Task to delete must exist           */
            ptcb->OSTCBDelReq = OS_TASK_DEL_REQ;                /* Set flag indicating task to be DEL. */
        }
        OS_EXIT_CRITICAL();
        return (OS_NO_ERR);
    }
}
#endif
/*$PAGE*/
#if OS_TASK_SUSPEND_EN
/*
*********************************************************************************************************
*                                            SUSPEND A TASK
*
* Description : This function is called to suspend a task.  The task can be the calling task if if the
*               priority passed to OSTaskSuspend() is the priority of the calling task.
* Arguments   : 'prio'     is the priority of the task to suspend.  If you specify OS_PRIO_SELF, the
*                          calling task will suspend itself and rescheduling will occur.
*
* Returns     : OS_NO_ERR                if the requested task is suspended
*               OS_TASK_SUSPEND_PRIO     if the task to suspend does not exist
* Note        : You should use this function with great care.  If you suspend a task that is waiting for
*               a message you will prevent this task from running when the message arrives.
*********************************************************************************************************
*/

UBYTE OSTaskSuspend(UBYTE prio)
{
    BOOLEAN   self;
    OS_TCB   *ptcb;


    if (prio == OS_LO_PRIO) {                                   /* Not allowed to suspend idle task    */
        return (OS_TASK_SUSPEND_IDLE);
    }
    if (prio >= OS_MAX_TASKS && prio != OS_PRIO_SELF) {         /* Make sure task priority is valid    */
        return (OS_PRIO_INVALID);
    }
    OS_ENTER_CRITICAL();
    if (prio == OS_PRIO_SELF) {                                 /* See if suspend SELF                 */
        prio = OSTCBCur->OSTCBPrio;
        self = TRUE;
    } else {
        self = FALSE;
    }
    if ((ptcb = OSTCBPrioTbl[prio]) == (OS_TCB *)0) {                /* Task to suspend must exist     */
        OS_EXIT_CRITICAL();
        return (OS_TASK_SUSPEND_PRIO);
    } else {
        if ((OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX) == 0) {     /* Make task not ready            */
            OSRdyGrp &= ~ptcb->OSTCBBitY;
        }
        ptcb->OSTCBStat |= OS_STAT_SUSPEND;                          /* Status of task is 'SUSPENDED'  */
        OS_EXIT_CRITICAL();
        if (self == TRUE) {                                          /* Context switch only if SELF    */
            OSSched();
        }
        return (OS_NO_ERR);
    }
}

/*$PAGE*/
/*
*********************************************************************************************************
*                                      RESUME A SUSPENDED TASK
*
* Description : This function is called to resume a previously suspended task.
* Arguments   : 'prio'     is the priority of the task to resume.
*
* Returns     : OS_NO_ERR                if the requested task is resumed
*               OS_TASK_RESUME_PRIO      if the task to resume does not exist
*               OS_TASK_NOT_SUSPENDED    if the task to resume has not been suspended
*********************************************************************************************************
*/

UBYTE OSTaskResume(UBYTE prio)
{
    OS_TCB   *ptcb;


    OS_ENTER_CRITICAL();
    if ((ptcb = OSTCBPrioTbl[prio]) == (OS_TCB *)0) {                /* Task to suspend must exist     */
        OS_EXIT_CRITICAL();
        return (OS_TASK_RESUME_PRIO);
    } else {
        if (ptcb->OSTCBStat & OS_STAT_SUSPEND) {                          /* Task must be suspended    */
            if ((ptcb->OSTCBStat &= ~OS_STAT_SUSPEND) == OS_STAT_RDY) {   /* Remove suspension         */
                OSRdyGrp               |= ptcb->OSTCBBitY;                /* Make task ready to run    */
                OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
                OS_EXIT_CRITICAL();
                OSSched();
            } else {
                OS_EXIT_CRITICAL();
            }
            return (OS_NO_ERR);
        } else {
            OS_EXIT_CRITICAL();
            return (OS_TASK_NOT_SUSPENDED);
        }
    }
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
*                             DELAY TASK 'n' TICKS   (n from 1 to 65535)
*
* Description : This function is called to delay execution of the currently running task until some time
*               expires.  If the specified delay is greater than 0 then a context switch will result.
* Arguments   : 'ticks'     is the time delay that the task will be suspended in 'ticks'.  Note that by
*                           specifying 0, the task will not be delayed.
*********************************************************************************************************
*/

void OSTimeDly(UWORD ticks)
{
    if (ticks > 0) {                                                      /* 0 means no delay!         */
        OS_ENTER_CRITICAL();
        if ((OSRdyTbl[OSTCBCur->OSTCBY] &= ~OSTCBCur->OSTCBBitX) == 0) {  /* Delay current task        */
            OSRdyGrp &= ~OSTCBCur->OSTCBBitY;
        }
        OSTCBCur->OSTCBDly = ticks;                                       /* Load ticks in TCB         */
        OS_EXIT_CRITICAL();
        OSSched();                                                        /* Find next task to run!    */
    }
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                         RESUME A DELAYED TASK
*********************************************************************************************************
*/

UBYTE OSTimeDlyResume(UBYTE prio)
{
    OS_TCB *ptcb;


    OS_ENTER_CRITICAL();
    ptcb = (OS_TCB *)OSTCBPrioTbl[prio];                   /* Make sure that task exist                */
    if (ptcb != (OS_TCB *)0) {
        if (ptcb->OSTCBDly != 0) {                         /* See if task is delayed                   */
            ptcb->OSTCBDly  = 0;                           /* Clear the time delay                     */
            if (!(ptcb->OSTCBStat & OS_STAT_SUSPEND)) {    /* See if task is ready to run              */
                OSRdyGrp               |= ptcb->OSTCBBitY; /* Make task ready to run                   */
                OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
                OS_EXIT_CRITICAL();
                OSSched();                                 /* See if this is new highest priority      */
            } else {
                OS_EXIT_CRITICAL();                        /* Task may be suspended                    */
            }
            return (OS_NO_ERR);
        } else {
            OS_EXIT_CRITICAL();
            return (OS_TIME_NOT_DLY);                      /* Indicate that task was not delayed       */
        }
    } else {
        OS_EXIT_CRITICAL();
        return (OS_TASK_NOT_EXIST);                        /* The task does not exist                  */
    }
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                         PROCESS SYSTEM TICK
*********************************************************************************************************
*/

void OSTimeTick(void)
{
    OS_TCB *ptcb;


    ptcb = OSTCBList;                                      /* Point at first TCB in TCB list           */
    while (ptcb->OSTCBPrio != OS_LO_PRIO) {                /* Go through all TCBs in TCB list          */
        OS_ENTER_CRITICAL();
        if (ptcb->OSTCBDly != 0) {                         /* Delayed or waiting for event with TO     */
            if (--ptcb->OSTCBDly == 0) {                   /* Decrement nbr of ticks to end of delay   */
                if (!(ptcb->OSTCBStat & OS_STAT_SUSPEND)) {    /* Is task suspended?                   */
                    OSRdyGrp               |= ptcb->OSTCBBitY; /* No,  Make task Rdy to Run (timed out)*/
                    OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
                } else {                                       /* Yes, Leave 1 tick to prevent ...     */
                    ptcb->OSTCBDly = 1;                        /* ... loosing the task when the ...    */
                }                                              /* ... suspension is removed.           */
            }
        }
        OS_EXIT_CRITICAL();
        ptcb = ptcb->OSTCBNext;                            /* Point at next TCB in TCB list            */
    }
    OS_ENTER_CRITICAL();                                   /* Update the 32-bit tick counter           */
    OSTime++;
    OS_EXIT_CRITICAL();
}
/*$PAGE*/
/*
*********************************************************************************************************
*                                           SET SYSTEM CLOCK
*********************************************************************************************************
*/

void OSTimeSet(ULONG ticks)
{
    OS_ENTER_CRITICAL();
    OSTime = ticks;
    OS_EXIT_CRITICAL();
}


/*
*********************************************************************************************************
*                                        GET CURRENT SYSTEM TIME
*********************************************************************************************************
*/

ULONG OSTimeGet(void)
{
    ULONG ticks;


    OS_ENTER_CRITICAL();
    ticks = OSTime;
    OS_EXIT_CRITICAL();
    return (ticks);
}
/*$PAGE*/
#if OS_SEM_EN
/*
*********************************************************************************************************
*                                         INITIALIZE SEMAPHORE
*********************************************************************************************************
*/

OS_EVENT *OSSemCreate(UWORD cnt)
{
    OS_EVENT *pevent;


    OS_ENTER_CRITICAL();